Disproportionation of alkylbenzenes

ABSTRACT

Disproportionation of alkylbenzenes is promoted by the use of catalysts prepared from antimony salts, optionally with cobalt or nickel salts, on alumina.

United States Paten 15] 3,663,265 Tabler et al. [4 1 June 6, 1972 [s41DISPROPORTIONATION OF 3,338,952 8/1967 Callahan et al ..252/464 BE Z S3,347,902 10/1967 Grasselli et al. ...252/464 3,392,001 7/1968 Lorenz etal ...252/464 [72] Inventors: Donald C. Tablet; Marvin M. Johnson,3,417,157 12/1968 Pollitzer ..260/672 both of Bartlesville, Okla. PrimaExaminer-Curtis R. Davis [73] Assignee: Phillips Petroleum CompanyAnomgy young and Quigg [22] Filed: Jan. 14, 1970 [57] ABSTRACT [21]Appl. No.: 2,971

Disproportlonatlon of alkylbenzenes is promoted by the use of catalystsprepared from antimony salts, optionally with cobalt [52] US. Cl...260/672 T, 252/464 or nickel salts, on alumina. [51] Int. Cl ..C07c3/62 [58] Field of Search ..260/672, 672 T; 252/464 [56] ReferencesCited 1 1 Claims, N0 Drawings UNITED STATES PATENTS 2/1957 Hughes et al...252/464 DISPROPORTIONATION F ALKYLBENZENES Our invention relates tothe disproportionation of alkylbenzenes. In another aspect, ourinvention relates to catalysts to effectuate disproportionationreactions of alkylbenzenes.

In modern petrochemical operations, aromatic hydrocarbons andparticularly the alkyl aromatic hydrocarbons are desired for a varietyof chemical processes, such as preparation of intermediates for polymerfonnation.

Crude oils are of a widely varying composition, and hence result invarying amounts of BTX, i.e., benzene, toluene, and the xylenes, as wellas other alkylbenzenes. The wide variety of processing conditions forthe crude oils, including cracking, refonning, and the like, also resultin various amounts and proportions of the aromatics.

It is. often desirable to convert available alkylbenzenes to products ofgreater and lesser numbers of alkyl groups, particularly if suchconversion can be accomplished without loss of aromaticity, i.e., withlittle or no formation of non-aromatic components either throughseverance of the benzene ring or through hydrogenation of the benzenering to cycloparaffins. Undesired conversion of aromatics tonon-aromatics complicates recovery and purification operations, as wellas being wastefulof the valuable aromatic components.

We have discovered that catalysts composed of antimony on an alumina,optionally together with either cobalt or nickel or both, are effectivein the disproportionation of toluene or other alkylbenzenessubstantially without formation of nonaromatics.

It is an object of our invention to improve the promotion ofdisproportionation reactions of alkylbenzenes. It is a further object toprovide unique catalysts. Other aspects, objects, and the severaladvantages of this invention will be apparent to one skilled in the artfrom the following description and appended claims.

The reaction to which we refer can be illustrated by:

in which R is an alkyl gro up having from one to about three carbonatoms, including methyl, ethyl, n-propyl, and isopropyl; n is an integerin the range of from 1 to 4; and m is either 1 or 2.

The catalysts which we have discovered and applied to disproportionation reactions include antimony on alumina, antimony withcobalt on alumina, antimony with nickel on alumina, and antimony withboth cobalt and nickel on alumina. The alumina can be selected from anyof the aluminas including fluoride compound-treated aluminas, as well asalumina combined with zirconia, titania, boria, or beryllia; thoughpreferably etaor gamma-alumina are used; and the term alumina should beso considered herein.

Our catalysts can contain from 1 to 20 weight per cent of antimony basedon the total alumina-containing composition, though more preferably from1 to 10 weight per cent antimony. The catalysts further can containcobalt or nickel or both, which result in improved effectiveness andlengthened life of the catalysts. Cobalt content can be from about 1 to15 weight per cent, though more preferably 5 to weight per cent. Thenickel content also can range from about 1 to weight per cent, thoughmore preferably from 5 to 10 weight per cent. When the catalyst containsboth cobalt and nickel, the combined amount of the two components canrange from about 1 to 15 weight per cent of the total catalystcomposition, again more preferably from 5 to 10 weight per cent. All ofthese values are of the constituent or constituents relative to thetotal weight of the catalyst composition. The state of the antimony,whether as the metal or in a combined state on the alumina, is not atpresent determinable. Therefore, in using the term antimony withreference to our prepared catalysts, we do not intend to limit toelemental antimony. Similarly, as to the cobalt and nickel components ofour catalysts.

The effectiveness of our catalysts is illustrated by runs shown in thefollowing examples which illustrate application of our catalysts to thedisproportionation processes; and further show one method of preparationof our catalysts.

EXAMPLE I A run was made utilizing an antimony on alumina catalyst,without the inclusion of cobalt or nickel. This catalyst was prepared byadding slowly 26 g (gram) of antimony pentachloride SbCl, to deionizedwater stirring, and the solution cooled in an ice bath. The mixture wasblended with 50 g of alumina to form a smooth paste. The alumina usedwas gamma-alumina, a very finely divided flame hydrolized aluminaprepared by reaction of aluminum chlorides with air at hightemperatures. 28 per cent ammonia water was added slowly, with stirring,until the admixture was slightly alkaline. The composition was dried at210 F. The dried material was crushed and screened to 10 to 40 mesh;calcined in air at 800 F. for 2 hours; then reduced in hydrogen at 875F. for 16 hours. In this run, the alkylbenzene feed was toluene, furthercontaining 0.7 volume per cent chloroform. Process conditions included1.33 Ll-ISV (liquid hourly space velocity), 912 F., 505 psig, and ahydrogen to hydrocarbon mole ratio of 0.92. Test results are shown after1 hour of operation, and after 4 hours:

Flame ionization detection determined gas liquid chromatographic areapercents (proportional to carbon percent) which are close approximationsof weight percents.

The antimony on alumina catalyst is shown to be quite effective withgood conversion. Further, no detectable amounts of non-aromatics wereformed, nor trialkyl products, in this run with the use of our catalystsfor disproportionation.

EXAMPLE II 33.9 g (0.136 mole) of cobalt acetate tetrahydrate wasdissolved in approximately 225 ml (milliliters) of deionized water, andthe solution cooled in a wet ice bath. To this mixture was slowly added13 ml of antimony pentachloride SbCl with stirring. A whitishprecipitate formed in slight amount. The mixture so formed was thenblended with 70 g of gammaalumina to form a smooth paste. To this pastewas slowly added 65 ml of 28 per cent ammonia solution, with stirring,such that the resulting paste was slightly alkaline to litmus paper. Thecolor of the mixture changed from light pink to a pink-purple color.This composition was then dried at 210 F. for 5 days; crushed andscreened to 10 to 40 mesh; calcined in air at 900 F. for 3 hours and at1,000 F. for 3 hours; and reduced in hydrogen at 800 F. for 2 hours. Thecomposition, a bright blue after calcination, turned black afterreduction.

The catalyst so prepared was placed in a reaction zone and contactedwith a toluene stream containing 0.7 per cent by volume CHCl Processconditions included a hydrogen stream such that a hydrogen tohydrocarbon mole ratio of 1.15 was effected at 1.3 ml/ml/hr LI-ISV; atemperature of 900 to 910 F and a pressure of 500 psig.

After 4 hours operation under these conditions, the conversion was 29.31per cent and the effluent stream had the fol lowing composition:

Refer Note 1 in Example l.

Comparing the 4-hour effluent analysis of Table l with the data in TableII, which also was taken at the end of a 4-hour operating cycle, theinitial and later effectiveness of the antimony-cobalt-alumina catalystis improved compared to the antimony-alumina catalyst of Example I. Theinclusion of the cobalt improves catalyst life and per cent conversionof the alkylbenzene.

Particularly noteworthy of the runs in both examples is the effectiveconversion to xylenes and benzene, without formation of paraffinproducts. And, only a relative trace of trialkylbenzene was produced inExample 11. The unconverted toluene, of course, can be separated andrecycled for additional conversion.

CATALYST PREPARATION-ACTIVATION For the preparation of our catalysts, aconvenient, effective, and presently preferred method is illustrated byExamples 1 and 11 above. However, any method resulting in the catalystsofour composition would be encompassed in our invention.

Examples of suitable antimony salts include antimony trifluoride,antimony pentafluoride, antimony trichloride sometimes known as butterof antimony, antimony pentachloride, and combinations of antimony withan organic component such as antimony tartrate, or double salts with analkali metal such as antimony potassium tartrate. With the antimonytrisalts, addition thereof to water tends to result in a slightprecipitation which is not objectionable, since the solution will bemade into a mixture with the substrate, and the entire admixtureincluding substrate then dried to form the catalysts of our invention.This method of preparation is particularly useful because of the ease ofhandling and lack of necessity to perform expensive separation steps,such as filtration, centrifuging, and the like.

Examples of suitable cobalt salts include cobaltic acetate, cobaltousacetate, cobaltous benzoate, cobaltous bromate, cobaltous bromide,cobaltous chlorate, cobaltous chloride, cobaltic chloride; theequivalent salts of fluorine and iodine; the formate, nitrate,propionate, sulfate, and even complex salts such as aquapentamminecobalt(Ill) chloride.

Examples of nickel salts include nickel bromide, nickel perchlorate,nickel chloride, nickel iodide, nickel nitrate, nickel sulfate, and evencomplex nickel salts such as hexamminenickel (ll) bromide and the like.Nickel salts of organic compounds such as nickel benzenesulfonate aresuitable.

The desired cobalt or nickel salt is dispersed in water, and theantimony salt added directly thereto; or the antimony salt can first bemixed with or dispersed in a small amount of water and the resultingdispersion then added to a dispersion of the cobalt or nickel salt.Preferably, the salts are water soluble. Preferably the amount of waterused is controlled in the antimony, or cobalt-antimony, ornickel-antimony, or cobaltnickel-antimony, salt admixture such that apaste or easily handled relatively thick mixture is formed when thesubstrate is added. While thinner mixtures are suitable, with additionalwater, this is unnecessary and only results in additional energyexpenditures to evaporate the excess water. Usually, the aluminasubstrate used is finely divided.

Neutralization of the admixture can be with any suitable alkalinematerial such as ammonia, ammonia water or ammonium hydroxide, or aminessuch as morpholine, cyclohexylamine, and the like, Ammonium hydroxide oran amine are preferable since such will volatilize upon heating of theneutralized complex. However, alkali metal hydroxides such as sodiumhydroxide, potassium hydroxide, lithium hydroxide, alone or incombination, can be used to neutralize the complex mixture; afterinitial drying, the complex so treated, however, requires washing toremove any excess alkali metal hydroxide present. Such a washing stepcan be omitted where a volatile alkaline material is used forneutralization.

After drying, the catalyst is calcined. Suitable calcinationtemperatures can range from about 800 to 1200 F though highertemperatures are not objectionable. Thereafter, the calcined catalyst isreduced in a stream of hydrogen at a temperature of from about 800 tol,O00 F. The catalyst then is ready for use in processes such asdescribed.

DISPROPORTIONATION CONDITIONS The disproportionation reaction can beconducted in any suitable reactor. A fixed bed, moving bed, or fluidizedbed of catalyst can be used. Reaction conditions for disproportionationinclude a temperature of from about 700 to l,O00 F., though preferablyfrom 800 to 950 F., a pressure of from about to 2,000 psig, thoughpreferably from 300 to 1,000 psig. Space velocities normally will rangefrom about 0.1 to 20 volumes of liquid hydrocarbon feed per volume ofcatalyst per hour, though more preferably between 0.5 and 2 areemployed. Hydrogen, optionally employed in the reaction for improvedconversion, is used in a hydrogen:hydrocarbon feed ratio of from about0.5:] to 10:1 moles of hydrogen per mole of hydrocarbon, more usually1:1 to 4:1. Diluents, known to the art, and which are inert under thereaction conditions, can be employed, if desired.

The feed of a halogen-containing compound improves the effectiveness ofthe catalysts in the disproportionation process. A hydrogen halide HXcan be fed where X can be selected from chlorine, fluorine, bromine, oriodine. A compound of the hydrocarbyl halide RX,, type also can beutilized, in which X is the same asjust described, and R can be anyhydrocarbyl radical including alkyl, alkaryl, aralkyl, cycloalkyl, aryl,cycloalkylalkyl, alkylcycloalkyl, or alkenyl that reacts under processconditions to produce HX. R can contain from one to about 10 carbons,though more usually a lower range of from one to about four carbon atomsis utilized for convenience. The hydrocarbyl radical can be olefinicallyunsaturated, if desired, as this is not objectionable. in the formulaRX,,, p is an integer and can range from 1 to about 4. More than 4halogen atoms per molecule are not objectionable; however, withincreasing numbers of halogen atoms, the molecule becomes progressivelyheavier, and volatility problems are encountered.

Examples of suitable hydrocarbyl halides RX, can include:

chloroform carbon tetrachloride bromomethane fluoromethane iodomethanedibromomethane l -ch1orodecane l-chlorol O-fluorodecane1-bromo-2-chloro-9-fluoro-10-iododecane l-fluoro-3-methyloctane3-chlorobutylbenzene bromomethylbenzenel-bromomethyl-2,3,S-trichlorobenzene 1-butyl-4-ch1orobenzene 1-ch1orocyclohexane 1-bromo-2,4-dichlorocyclodecane1,2,4,5-tetrabromobenzene chlorobenzene 2-chloronaphthalenel-bromo-4-butylcyclohexane 4-chlorobutylcyclohexanel-iodo-4-(4-chlorobutyl)cyclohexane vinyl chloride l -chloro-3 -hexenel-fluoro-3-iodo-5-decene, and the like.

The amount of halogen-containing compound employed should be such thatthe halogen content in the feed to the reaction zone is in the range offrom about 50 to 10,000 parts per million by weight of halogen relativeto the feed of hydrocarbon, excluding hydrogen and any diluent.

Normally, it is preferable to avoid the use of free halogen gases suchas fluorine, chlorine, bromine, iodine. While such are operable withinthe framework of our process, yet the tendency is to result inhalogenation losses of the hydrocarbon feedstock. Further, free bromineand iodine are highly corrosive to the reactor itself. Nevertheless,since such are operable, the term halogen-containing compound isintended to include the free halogens.

CATALYST REACTIVATION The catalyst to be reactivated after a time onstream is ca]- cined in the presence of oxygen or an oxygen-containingstream, at a temperature similar to the range as used for initialpreparation-activation. Calcination is followed by reduction withhydrogen as described under catalyst regeneration-activation. Followingreduction, treatment with HX or RX should be applied in order for thecatalyst to be most promptly active for disproportionation. It ispossible to omit the treatment of the catalyst with HX or R'X,,, and touse the catalyst immediately for disproportionation, by feeding ahalogen-containing compound to the reactor, either with the hydrocarbonfeed or separately, so as to complete the reactivation of the catalyst.However, such method in practice is preceded with an interval or lagtime during which the catalyst is not active or at least not fullyactive. Therefore, it' is preferable for the halogen treatment to beapplied to the reduced catalyst near the end of the reduction withhydrogen, or. even subsequent to the reduction with hydrogen, in orderfor the catalyst to be fully active for the disproportionation process.

The foregoing discussion and examples have illustrated the effectivenessof our catalysts, particularly the effectiveness of our catalystsrelative to their use in disproportionation processes. Reasonablevariations and modifications of our invention are possible within thescope of our disclosure without departing from the scope and spirit asdisclosed in this specification and claims.

We claim:

1. An antimony on alumina catalyst composition consisting essentially ofreduced antimony or antimony compound and further containing at leastone of cobalt or nickel, said alumina selected from at least one of analumina, a fluoride compound-treated alumina, and an alumina combinedwith at least one of zirconia, titania, boria, beryllia combinationsthereof, and mixtures thereof, wherein said antimony on alumina catalystcomposition contains from about 1 to about 20 weight per cent of saidantimony, and from about 1 to weight per cent of said cobalt or nickel.

2. A catalyst according to claim 1 wherein said catalyst contains fromabout 1 to about 10 weight per cent of said antimony, and from about 5to about 10 weight per cent of at least one of said cobalt and nickel.

3. A method of preparing a catalyst comprising antimony on alumina, saidalumina selected from at least one of an alumina, a fluoridecompound-treated alumina, and an alumina combined with at least one ofzirconia, titania, boria, beryllia,

combinations thereof, and mixtures thereof, wherein said catalystcontains from about 1 to about 20 weight per cent of said antimony, saidcatalyst further containing at least one of cobalt and nickel such thatsaid catalyst contains from about 1 to about 15 weight per cent of atleast one of said cobalt and nickel, said method comprising the stepsof:

a. bringing together in aqueous dispersion a salt of said antimony, asalt of at least one of said cobalt and nickel, and said alumina,

b. neutralizing said dispersion with an alkaline material,

c. dewatering said dispersion, thereby leaving a dried composition,

d. calcining said dried composition,

e. reducing said calcined composition in the presence of hydrogen, and

thereby producing said catalyst.

4. A method of preparing said catalyst according to claim 3 wherein saidantimony salt is a water soluble antimony salt; said salt of at leastone of cobalt and nickel is a water soluble salt; and wherein saidneutralizing step is accomplished by utilizing at least one of ammonia,a strongly basic amine, and an alkali metal hydroxide.

5. A method of preparing said catalyst composition according to claim 4wherein the neutralizing step is accomplished with at least one alkalimetal hydroxide, and the neutralized composition is washed so as tosubstantially remove excess alkali metal hydroxide.

6. A process for the disproportionation of alkylbenzenes which comprisescontacting at least one alkylbenzene with a catalyst selected from atleast one of antimony on an alumina substrate, antimony and cobalt on analumina substrate, antimony and nickel on an alumina substrate, andantimony and cobalt and nickel on an alumina substrate, underdisproportionation conditions.

7. A process according to claim 6 wherein said alumina substrate isselected from at least one of alumina, fluoride compound-treatedalumina, alumina combined with at least one of zirconia, titania, boria,and beryllia, combinations thereof, and mixtures thereof.

8. A process according to claim 6 wherein said alkylbenzene isrepresented by the formula wherein R is an alkyl group having from oneto about three carbon atoms, n is an integer in the range of from 1 to4, and wherein the products of said disproportionation include wherein mneither Kiri? 9. A process according to claim 8 wherein saiddisproportionation conditions include from about 1:1 to about 10:1 molesof hydrogen per mole of hydrocarbon feed, a reaction zone temperature offrom about 700 to about 1,000 E, a reaction zone pressure of from aboutto about 2,000 psig, and a space velocity of from about 0.1 to about 20volumes of liquid feed per volume of catalyst per hour.

10. A process according to claim 9 wherein further is employed ahalogen-containing compound in an amount constituting from about 50 toabout 10,000 parts per million by weight as halogen relative to saidalkylbenzene.

11. A process according to claim 10 wherein said halogencontainingcompound is selected from at least one of HX and R'X wherein X isselected from at least one of fluorine, chlorine, bromine, and iodine,R' is a hydrocarbyl radical containing from one to about 10 carbonatoms, and p is an integer of from 1 to about 4.

2. A catalyst according to claim 1 wherein said catalyst contains fromabout 1 to about 10 weight per cent of said antimony, and from about 5to about 10 weight per cent of at least one of said cobalt and nickel.3. A method of preparing a catalyst comprising antimony on alumina, saidalumina selected from at least one of an alumina, a fluoridecompound-treated alumina, and an alumina combined with at least one ofzirconia, titania, boria, beryllia, combinations thereof, and mixturesthereof, wherein said catalyst contains from about 1 to aboUt 20 weightper cent of said antimony, said catalyst further containing at least oneof cobalt and nickel such that said catalyst contains from about 1 toabout 15 weight per cent of at least one of said cobalt and nickel, saidmethod comprising the steps of: a. bringing together in aqueousdispersion a salt of said antimony, a salt of at least one of saidcobalt and nickel, and said alumina, b. neutralizing said dispersionwith an alkaline material, c. dewatering said dispersion, therebyleaving a dried composition, d. calcining said dried composition, e.reducing said calcined composition in the presence of hydrogen, andthereby producing said catalyst.
 4. A method of preparing said catalystaccording to claim 3 wherein said antimony salt is a water solubleantimony salt; said salt of at least one of cobalt and nickel is a watersoluble salt; and wherein said neutralizing step is accomplished byutilizing at least one of ammonia, a strongly basic amine, and an alkalimetal hydroxide.
 5. A method of preparing said catalyst compositionaccording to claim 4 wherein the neutralizing step is accomplished withat least one alkali metal hydroxide, and the neutralized composition iswashed so as to substantially remove excess alkali metal hydroxide.
 6. Aprocess for the disproportionation of alkylbenzenes which comprisescontacting at least one alkylbenzene with a catalyst selected from atleast one of antimony on an alumina substrate, antimony and cobalt on analumina substrate, antimony and nickel on an alumina substrate, andantimony and cobalt and nickel on an alumina substrate, underdisproportionation conditions.
 7. A process according to claim 6 whereinsaid alumina substrate is selected from at least one of alumina,fluoride compound-treated alumina, alumina combined with at least one ofzirconia, titania, boria, and beryllia, combinations thereof, andmixtures thereof.
 8. A process according to claim 6 wherein saidalkylbenzene is represented by the formula wherein R is an alkyl grouphaving from one to about three carbon atoms, n is an integer in therange of from 1 to 4, and wherein the products of saiddisproportionation include wherein m is either 1 or
 2. 9. A processaccording to claim 8 wherein said disproportionation conditions includefrom about 1:1 to about 10: 1 moles of hydrogen per mole of hydrocarbonfeed, a reaction zone temperature of from about 700* to about 1,000* F.,a reaction zone pressure of from about 100 to about 2,000 psig, and aspace velocity of from about 0.1 to about 20 volumes of liquid feed pervolume of catalyst per hour.
 10. A process according to claim 9 whereinfurther is employed a halogen-containing compound in an amountconstituting from about 50 to about 10,000 parts per million by weightas halogen relative to said alkylbenzene.
 11. A process according toclaim 10 wherein said halogen-containing compound is selected from atleast one of HX and R''Xp wherein X is selected from at least one offluorine, chlorine, bromine, and iodine, R'' is a hydrocarbyl radicalcontaining from one to about 10 carbon atoms, and p is an integer offrom 1 to about 4.